/Engine/Source/Runtime/InteractiveToolsFramework/Public/BaseGizmos/CombinedTransformGizmo.h
Set a new position for the Gizmo. This is done via the same mechanisms as the sub-gizmos, so it generates the same Change/Modify() events, and hence works with Undo/Redo
virtual void SetNewGizmoTransform ( const FTransform & NewTransform, bool bKeepGizmoUnscaled )